A DNA-based molecular device switchable between three distinct mechanical states

A self-assembled DNA-based molecular device is described which can be switched between three distinct mechanical states. The device consists of two supramolecular arms connected by a hinge. The arms can be in a closed, relaxed, or stretched configuration. The operation of the device is monitored by fluorescence resonance energy transfer. Variations in the design of the device have a strong influence on the operation kinetics of the device.(C) 2002 American Institute of Physics.